Some sites wont connect

[ArtLyso]

I am running firefox. I am on a wireless network. I am having problems with some websites not being found. I have guessed that there is a problem with the connection, but I am wondering why most sites are loading, but only some random sites wont be found. If there is a problem with the connection then why aren't all the sites not being found? Why are only a few sites not being found?

[degsy]

Is there a connection between the sites?
Are they secure such as banking sites? Are they in the same country?

[renegade600]

give an url of a site not loading

[ArtLyso]

They arent secure sites. They are just normal sites. They are dot com sites. Not 100% sure what country they are located in.